First, calculate the price of the car WITH the tax rate.
8.5% → 0.085
$5900 × 0.085 = $501.50
Add the tax, to the original price.
$5900 + $501.50 = $6401.50
Next, get the 15% downpayment
15% → 0.15
$6401.50 × 0.15 = $960.225
Rounding off to the nearest cent, the downpayment is equal to $960.23.